Methods and apparatus for assigning resources to schedule peer-to-peer communications in wwan

ABSTRACT

A method of operating a wireless device includes determining an energy on each of a plurality of resources for broadcasting CIDs, sending information to a base station based on the determined energy for each of the CIDs, and receiving a CID from the base station. The received CID is one of the CIDs determined based on the information. A method of wireless communication includes receiving first information about a first plurality of CIDs from a first wireless device, receiving second information about a second plurality of CIDs from a second wireless device, comparing the first information and the second information to determine a subset of CIDs based on the first plurality of CIDs and the second plurality of CIDs, selecting a CID based on the subset of CIDs, and sending the selected CID to at least one of the first wireless device or the second wireless device.

BACKGROUND

1. Field

The present disclosure relates generally to communication systems, andmore particularly, to assigning resources to schedule peer-to-peercommunications in wireless wide area network (WWAN) communication.

2. Background

In WWAN, all communications between wireless devices go throughuplink/downlink channels between wireless devices and base stations.When two communicating wireless devices are in the vicinity of eachother, to reduce a load on the base station, the two wireless devicesmay use direct peer-to-peer communication instead of the uplink/downlinkchannels through the base station. When there are multiple peer-to-peercommunications (i.e., multiple links) in proximity of one another, linkscheduling becomes necessary to control cross link interference. Linkscheduling may be performed through a set of dedicated orthogonaltime-frequency resources in addition to the peer-to-peer datacommunication resources. The dedicated connection scheduling resourcesallow links to exchange information in a distributed manner in order todetermine which set of links may transmit in the peer-to-peer datacommunication resources.

To avoid collisions in the connection scheduling resources, links in thevicinity of each other may be assigned different resources. Theallocation of different resources allow links to transmit on theirassigned connection scheduling resources and receive on all remainingconnection scheduling resources in order to determine the cross linkinterference and to determine which links may transmit in thepeer-to-peer data communication resources based on the cross linkinterference. How links are allocated different resources is thereforeimportant. There is a current need in the art for improving the processfor assigning different resources to various links.

SUMMARY

In an aspect of the disclosure, a method, an apparatus, and a computerprogram product are provided in which an energy on each of a pluralityof resources is determined for broadcasting connection identifiers.Information is sent to a base station based on the determined energy foreach of the connection identifiers. A connection identifier is receivedfrom the base station. The connection identifier is one of theconnection identifiers determined based on the information.

In an aspect of the disclosure, a method, an apparatus, and a computerprogram product for wireless communication are provided in which firstinformation about a first plurality of connection identifiers isreceived from a first wireless device. Second information about a secondplurality of connection identifiers is received from a second wirelessdevice. The first information and the second information are compared todetermine a subset of connection identifiers based on the firstplurality of connection identifiers and the second plurality ofconnection identifiers. A connection identifier is selected based on thesubset of connection identifiers. The selected connection identifier issent to at least one of the first wireless device or the second wirelessdevice.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a hardware implementationfor an apparatus employing a processing system.

FIG. 2 is a drawing of a wireless peer-to-peer communications system.

FIG. 3 is a diagram illustrating a time structure for peer-to-peercommunication between the wireless devices.

FIG. 4 is a diagram illustrating the channels in each frame ofsuperframes in one grandframe.

FIG. 5 is a diagram illustrating an operation timeline of amiscellaneous channel and a structure of a connection identifierbroadcast.

FIG. 6 is a diagram illustrating an operation timeline of a trafficchannel slot and a structure of connection scheduling.

FIG. 7 is a first diagram for illustrating a connection schedulingsignaling scheme for the wireless devices.

FIG. 8 is a second diagram for illustrating a connection schedulingsignaling scheme for the wireless devices.

FIG. 9 is a diagram for illustrating exemplary methods.

FIG. 10 is a diagram for illustrating the cascade yielding problem.

FIG. 11 is a flow chart of a first method of a wireless device.

FIG. 12 is a flow chart of a second method of a wireless device.

FIG. 13 is a conceptual block diagram illustrating the functionality ofa first exemplary apparatus.

FIG. 14 is a flow chart of a first method of a base station.

FIG. 15 is a flow chart of a second method of a base station.

FIG. 16 is a conceptual block diagram illustrating the functionality ofa second exemplary apparatus.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of communication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawing by various blocks, modules, components,circuits, steps, processes, algorithms, etc. (collectively referred toas “elements”). These elements may be implemented using electronichardware, computer software, or any combination thereof Whether suchelements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented with a “processing system”that includes one or more processors. Examples of processors includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. One or more processors in theprocessing system may execute software. Software shall be construedbroadly to mean instructions, instruction sets, code, code segments,program code, programs, subprograms, software modules, applications,software applications, software packages, routines, subroutines,objects, executables, threads of execution, procedures, functions, etc.,whether referred to as software, firmware, middleware, microcode,hardware description language, or otherwise. The software may reside ona computer-readable medium. The computer-readable medium may be anon-transitory computer-readable medium. A non-transitorycomputer-readable medium include, by way of example, a magnetic storagedevice (e.g., hard disk, floppy disk, magnetic strip), an optical disk(e.g., compact disk (CD), digital versatile disk (DVD)), a smart card, aflash memory device (e.g., card, stick, key drive), random access memory(RAM), read only memory (ROM), programmable ROM (PROM), erasable PROM(EPROM), electrically erasable PROM (EEPROM), a register, a removabledisk, and any other suitable medium for storing software and/orinstructions that may be accessed and read by a computer. Thecomputer-readable medium may be resident in the processing system,external to the processing system, or distributed across multipleentities including the processing system. The computer-readable mediummay be embodied in a computer-program product. By way of example, acomputer-program product may include a computer-readable medium inpackaging materials.

Accordingly, in one or more exemplary embodiments, the functionsdescribed may be implemented in hardware, software, firmware, or anycombination thereof. If implemented in software, the functions may bestored on or encoded as one or more instructions or code on acomputer-readable medium. Computer-readable media includes computerstorage media. Storage media may be any available media that can beaccessed by a computer. By way of example, and not limitation, suchcomputer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media. Those skilled in the art will recognize howbest to implement the described functionality presented throughout thisdisclosure depending on the particular application and the overalldesign constraints imposed on the overall system.

FIG. 1 is a conceptual diagram illustrating an example of a hardwareimplementation for an apparatus 100 employing a processing system 114.The processing system 114 may be implemented with a bus architecture,represented generally by the bus 102. The bus 102 may include any numberof interconnecting buses and bridges depending on the specificapplication of the processing system 114 and the overall designconstraints. The bus 102 links together various circuits including oneor more processors, represented generally by the processor 104, andcomputer-readable media, represented generally by the computer-readablemedium 106. The bus 102 may also link various other circuits such astiming sources, peripherals, voltage regulators, and power managementcircuits, which are well known in the art, and therefore, will not bedescribed any further. A bus interface 108 provides an interface betweenthe bus 102 and a transceiver 110. The transceiver 110 provides a meansfor communicating with various other apparatuses over a transmissionmedium.

The processor 104 is responsible for managing the bus 102 and generalprocessing, including the execution of software stored on thecomputer-readable medium 106. The software, when executed by theprocessor 104, causes the processing system 114 to perform the variousfunctions described infra for any particular apparatus. Thecomputer-readable medium 106 may also be used for storing data that ismanipulated by the processor 104 when executing software.

FIG. 2 is a drawing of an exemplary peer-to-peer communications system200. The peer-to-peer communications system 200 includes a plurality ofwireless devices 206, 208, 210, 212. The peer-to-peer communicationssystem 200 may overlap with a cellular communications system, such asfor example, a wireless wide area network (WWAN). Some of the wirelessdevices 206, 208, 210, 212 may communicate together in peer-to-peercommunication, some may communicate with the base station 204, and somemay do both. For example, as shown in FIG. 2, the wireless devices 206,208 are in peer-to-peer communication and the wireless devices 210, 212are in peer-to-peer communication. The wireless device 212 is alsocommunicating with the base station 204.

The wireless device may alternatively be referred to by those skilled inthe art as user equipment, a mobile station, a subscriber station, amobile unit, a subscriber unit, a wireless unit, a wireless node, aremote unit, a mobile device, a wireless communication device, a remotedevice, a mobile subscriber station, an access terminal, a mobileterminal, a wireless terminal, a remote terminal, a handset, a useragent, a mobile client, a client, or some other suitable terminology.The base station may alternatively be referred to by those skilled inthe art as an access point, a base transceiver station, a radio basestation, a radio transceiver, a transceiver function, a basic serviceset (BSS), an extended service set (ESS), a Node B, an evolved Node B,or some other suitable terminology.

The exemplary methods and apparatuses discussed infra are applicable toany of a variety of wireless peer-to-peer communications systems, suchas for example, a wireless peer-to-peer communication system based onFlashLinQ, WiMedia, Bluetooth, ZigBee, or Wi-Fi based on the IEEE 802.11standard. To simplify the discussion, the exemplary methods andapparatus are discussed within the context of FlashLinQ. However, one ofordinary skill in the art would understand that the exemplary methodsand apparatuses are applicable more generally to a variety of otherwireless peer-to-peer communication systems.

FIG. 3 is a diagram 300 illustrating a time structure for peer-to-peercommunication between the wireless devices 100. An ultraframe is 512seconds and includes 64 megaframes. Each megaframe is 8 seconds andincludes 8 grandframes. Each grandframe is 1 second and includes 15superframes. Each superframe is approximately 66.67 ms and includes 32frames. Each frame is 2.0833 ms.

FIG. 4 is a diagram 310 illustrating the channels in each frame ofsuperframes in one grandframe. In a first superframe (with index 0),frame 0 is a reserved channel (RCH), frames 1-10 are each amiscellaneous channel (MCCH), and frames 11-31 are each a trafficchannel (TCCH). In the 2^(nd) through 7^(th) superframes (with index1:6), frame 0 is a RCH and frames 1-31 are each a TCCH. In an 8^(th)superframe (with index 7), frame 0 is a RCH, frames 1-10 are each aMCCH, and frames 11-31 are each a TCCH. In the 9^(th) through 15^(th)superframes (with index 8:14), frame 0 is a RCH and frames 1-31 are eacha TCCH. The MCCH of superframe index 0 includes a secondary timingsynchronization channel, a peer discovery channel, a peer page channel,and a reserved slot. The MCCH of superframe index 7 includes a peer pagechannel and reserved slots. The TCCH includes connection scheduling, apilot, channel quality indicator (CQI) feedback, a data segment, and anacknowledgement (ACK).

FIG. 5 is a diagram 330 illustrating an operation timeline of the MCCHand a structure of a connection identifier (CID) broadcast. As discussedin relation to FIG. 4, the MCCH of superframe index 0 includes asecondary timing synchronization channel, a peer discovery channel, apeer paging channel, and a reserved slot. The peer paging channel in theMCCH of superframe index 0 includes a quick paging channel, a CIDbroadcast channel, and a page request channel. The MCCH of superframeindex 7 includes a peer paging channel and a reserved slot. The peerpaging channel in the MCCH of superframe index 7 includes a pageresponse channel and a page confirm channel. The CID broadcast channelprovides a distributed protocol for CID allocations for new connections,provides a mechanism for CID collision detection, and provides awireless device evidence that its link connection with a communicationpeer still exists.

The structure of the CID broadcast consists of four blocks, each ofwhich contains a plurality of resource elements, i.e., a plurality ofsubcarriers in the frequency domain and OFDM symbols in the time domain.Each of the four blocks spans a plurality of subcarriers (e.g., 28subcarriers) and includes 16 OFDM symbols. One resource element (ortone) corresponds to one subcarrier and one OFDM symbol.

For each CID, a pair of resource elements in adjacent OFDM symbols isallocated in each of the four blocks for the CID broadcast. In a pair ofadjacent resource elements, a first resource element carries an energyproportional to a power used to transmit in the TCCH and a secondresource element carries an energy inversely proportional to a powerreceived in the TCCH. If an additional resource element is allocated foreach CID, the wireless devices may also transmit a device identifier sothat other wireless devices may determine which wireless device is usinga particular CID. For a given CID, each pair of resource elements has afixed OFDM symbol position and a varying subcarrier within the blockthat varies each grandframe. In any given link, the wireless device thatinitiated the link randomly selects a block from Block 0 and Block 2 forthe CID broadcast and the other wireless device in the link randomlyselects a block from Block 1 and Block 3 for the CID broadcast. As such,for a particular CID, only half of the allocated resources are utilizedby a link with that CID. Due to the random selection of a block, a firstwireless device in a link with a second wireless device will be able todetect a CID collision when a third wireless device or a fourth wirelessdevice in a different link transmits a CID broadcast using a blockdifferent than the block selected by the first wireless device or thesecond wireless device.

For example, assume a wireless device with a CID=4 selects Block 0 forthe CID broadcast. The wireless device may be allocated resourceelements 332, 334 for the CID broadcast. In resource element 332, thewireless device transmits an energy proportional to a power used totransmit in the TCCH. In resource element 334, the wireless devicetransmits an energy inversely proportional to a power received in theTCCH. In a subsequent grandframe, the wireless device may have adifferent pair of resource elements with a different subcarrier, but thesame relative OFDM symbol position (i.e., in this example, the first andthe second OFDM symbol of the selected block).

FIG. 6 is a diagram 340 illustrating an operation timeline of a TCCHslot and a structure of connection scheduling. As shown in FIG. 6, aTCCH slot includes four subchannels: connection scheduling, ratescheduling, data segment, and ACK. The rate scheduling subchannelincludes a pilot segment and a CQI segment. The ACK subchannel is fortransmitting an ACK or negative ACK (NACK) in response to data receivedin the data segment subchannel. The connection scheduling subchannelincludes two blocks, a higher priority Block H and a lower priorityBlock L. Each of Block H and Block L contains a plurality of resourceelements, i.e., a plurality of subcarriers in the frequency domain andOFDM symbols in the time domain. Each of Block H and Block L spans theplurality of subcarriers and includes four OFDM symbols in a Txp-block,four OFDM symbols in a Tx-block, and four OFDM symbols in an Rx-block.One resource element (or tone) corresponds to one subcarrier and oneOFDM symbol.

Each link has a CID. Based on the CID, for a particular TCCH slot,wireless devices in a link are allocated a resource element in the samerespective OFDM symbol position in each of the Txp-block, the Tx-block,and the Rx-block at a particular subcarrier and within Block H or BlockL. For example, in a particular TCCH slot, a link with CID=4 may beallocated the resource element 342 in the Txp-block of Block H, theresource element 344 in the Tx-block of Block H, and the resourceelement 346 in the Rx-block of Block H for transmitting/receiving ascheduling control signal. A transmit request signal in the Tx-block istransmitted with a power equal to a power for transmitting the datasegment. A transmit request response signal in the Rx-block istransmitted with a power proportional to an inverse of the power of thereceived transmit request signal. The allocated trio of resourceelements for the Txp-block, Tx-block, and Rx-block vary with respect tothe subcarrier (e.g., k different subcarriers) and the respective OFDMsymbol in each TCCH slot (e.g., 8 different OFDM symbols—4 in the BlockH and 4 in the Block L).

The trio of resource elements allocated to a link dictates the mediumaccess priority of the link. For example, the trio of resource elements342, 344, 346 corresponds to i=2 and j=1. The medium access priority isequal to ki+j+1, where i is the respective OFDM symbol in each of theTxp, Tx, and Rx subblocks, j is the subcarrier, and k is the number ofsubcarriers. Accordingly, assuming k=28, the resource elements 342, 344,346 correspond to a medium access priority of 58.

FIG. 7 is a first diagram 360 for illustrating an exemplary connectionscheduling signaling scheme for the wireless devices 100. As shown inFIG. 7, wireless device A is communicating with wireless device B,wireless device C is communicating with wireless device D, and wirelessdevice E is communicating with wireless device F. The wireless device Ais assumed to have transmit priority over the wireless device B, thewireless device C is assumed to have transmit priority over the wirelessdevice D, and the wireless device E is assumed to have transmit priorityover the wireless device F. Each of the links has a different mediumaccess priority depending on the particular slot for communication. Forthe particular slot for communication, link 1 (A, B) is assumed to havea medium access priority of 2, link 2 (C, D) is assumed to have a mediumaccess priority of 1, and link 3 (E, F) is assumed to have a mediumaccess priority of 7.

FIG. 8 is a second diagram 370 for illustrating an exemplary connectionscheduling signaling scheme for the wireless devices 100. FIG. 8 showsconnection scheduling resources of first respective OFDM symbols (i=0,see FIG. 6) of Txp, Tx, and Rx subblocks in Block H (corresponding tomedium access priorities 1 through k) in the connection schedulingsubchannel. The connection scheduling resources include a plurality ofsubcarriers, each of the subcarriers corresponding to one of k frequencybands. Each of the frequency bands corresponds to a particular mediumaccess priority. One block in the connection scheduling resources issplit into three subblocks/phases: Txp, Tx, and Rx. The Txp-block isused by the node with transmit priority in the link to indicate whetherthe node with transmit priority will act as a transmitter or a receiver.If the node with transmit priority transmits on the allocated OFDMsymbol in the Txp-block, the node with transmit priority indicates tothe node without transmit priority an intent to act as a transmitter. Ifthe node with transmit priority does not transmit on the allocated OFDMsymbol in the Txp-block, the node with transmit priority indicates tothe node without transmit priority an intent to act as a receiver. TheTx-block is used by potential transmitters to make a request to bescheduled. The transmitter transmits a direct power signal on theallocated OFDM symbol in the Tx-block at a power equal to a power usedfor the traffic channel (i.e., a power for transmitting the datasegment). Each potential receiver listens to the tones in the Tx-blocks,compares the received power on each of the Tx-blocks to the receivedpower on the Tx-block allocated to the transmitter of its own link, anddetermines whether to Rx-yield based on its own link medium accesspriority relative to other link medium access priorities and thecomparison.

For example, assume the nodes A, D, and E transmit a transmit requestsignal in the Tx-block at a power equal to P_(A), P_(D), and P_(E),respectively. The node B receives the transmit request signal from thenode A at a power equal to P_(A)|h_(AB)|², where h_(AB) is the pathlossbetween the node A and the node B. The node B receives the transmitrequest signal from the node D with a power equal to P_(D)|h_(DB)|²,where h_(DB) is the pathloss between the node D and the node B. The nodeB receives the transmit request signal from the node E with a powerequal to P_(E)|h_(EB)|², where h_(EB) is the pathloss between the node Eand the node B. The node B compares the power of the received transmitrequest signal from the node A divided by the sum of the powers of thereceived transmit request signals from other nodes with a higherpriority to a threshold in order to determine whether to Rx-yield. Thenode B does not Rx-yield if the node B expects a reasonable signal tointerference ratio (SIR) if scheduled. That is, the node B Rx-yieldsunless P_(A)|h_(AB)|²/P_(D)|h_(DB)|²>Y_(RX), where y_(RX) is thethreshold (e.g., 9 dB).

The Rx-block is used by the potential receivers. If the receiver choosesto Rx-yield, the receiver does not transmit in the allocated OFDM symbolin the Rx-block; otherwise, the receiver transmits an inverse echo powersignal in the allocated OFDM symbol in the Rx-block at a powerproportional to an inverse of the power of the received direct powersignal from the transmitter of its own link. All of the transmitterslisten to the tones in the Rx-block to determine whether to Tx-yieldtransmission of the data segment.

For example, the node C, having received the transmit request signalfrom the node D at a power equal to P_(D)|h_(DC)|², transmits a transmitrequest response signal in the Rx-block at a power equal toK/P_(D)|h_(DC)|², where h_(DC) is the pathloss between the node D andthe node C, and K is a constant known to all nodes. The node A receivesthe transmit request response signal from the node C at a power equal toK|h_(CA)|²/P_(D)|h_(DC)|², where h_(CA) is the pathloss between the nodeC and the node A. The node A Tx-yields if the node A would cause toomuch interference to the node C. That is, the node A Tx-yields unlessP_(D)|h_(DC)|²/P_(A)|h_(CA)|²>Y_(TX), where Y_(TX) is a threshold (e.g.,9 dB).

The connection scheduling signaling scheme is best described inconjunction with an example. The node C has no data to transmit and doesnot transmit in the Txp-block for medium access priority 1, the node Ahas data to transmit and transmits in the Txp-block for medium accesspriority 2, and the node E has data to transmit and transmits in theTxp-block for medium access priority 7. The node D has data to transmitand transmits in the Tx-block for medium access priority 1, the node Atransmits in the Tx-block for medium access priority 2, and the node Etransmits in the Tx-block for medium access priority 7. The node Clistens to the tones in the Tx-blocks and determines to transmit in theRx-block for medium access priority 1, as the node C has the highestpriority. The node B listens to the tones in the Tx-blocks, determinesthat its link would not interfere with link 2, which has a higher mediumaccess priority, and transmits in the Rx-block for medium accesspriority 2. The node F listens to the tones in the Tx-blocks, determinesthat its link would interfere with link 1 and/or link 2, both of whichhave a higher medium access priority, and Rx-yields by not transmittingin the Rx-block for medium access priority 7. Subsequently, both D and Alisten to the tones in the Rx blocks to determine whether to transmitthe data. Because D has a higher link medium access priority than A, Dtransmits its data. A will Tx-yield transmission of the data if Adetermines that its transmission would interfere with the transmissionfrom D.

FIG. 9 is a diagram 400 for illustrating exemplary methods. As discussedsupra, the proper selection of a CID allows a link to avoid CIDcollisions and to participate in connection scheduling (see FIG. 6 andrelated discussion) in a distributed manner in order to determine across link interference with other communicating links and to determinewhether to transmit in the data segment channel based on the determinedcross link interference (see FIGS. 7, 8 and related discussion). Assuch, the selection of the CID is important. According to the exemplarymethods, the base station 402 selects a CID for a link based oninformation gathered by wireless devices participating in the link andmay also select the CID for a link based on information gathered bywireless devices not participating in the link (e.g., wireless devicesparticipating in other links). As shown in FIG. 9, the wireless device404A and the wireless device 404B would like to establish a linktogether, the wireless devices 406A, 406B are in peer-to-peercommunication with CID1, the wireless devices 407A, 407B are inpeer-to-peer communication with CID2, the wireless devices 408A, 408Bare in peer-to-peer communication with CID3, and the wireless devices409A, 409B are in peer-to-peer communication with CID4. In a pluralityof resources for broadcasting CIDs (e.g., the CID broadcast channelresources of FIG. 5), the wireless devices 406A, 406B are broadcastingsignals in resources allotted for CID1, the wireless devices 407A, 407Bare broadcasting signals in resources allotted for CID2, the wirelessdevices 408A, 408B are broadcasting signals in resources allotted forCID3, and the wireless devices 409A, 409B are broadcasting signals inresources allotted for CID4.

According to an exemplary method, the wireless devices 404A, 404B eachdetermine an energy on each of a plurality of resources for broadcastingCIDs. For example, the wireless devices 404A, 404B may determine anenergy on each of the resources allotted to CID1, CID2, CID3, and CID4.The wireless device 404A may determine than the energy on resourcesallotted to CID 1 and CID3 is above a threshold and that the energy onresources allotted to CID2 and CID4 is below a threshold. The wirelessdevice 404B may determine that the energy on resources allotted to CID2and CID3 is above a threshold and that the energy on resources allottedto CID1 and CID4 is below a threshold. The wireless devices 404A, 404Bmay also rank the CIDs or a subset of the CIDs based on the determinedenergies. For example, the wireless device 404A may rank the CIDs in theorder CID1, CID3, CID2, CID4 and the wireless device 404B may rank theCIDs in the order CID2, CID3, CID1, CID4.

After determining an energy on each of the plurality of resources forbroadcasting CIDs, the wireless devices 404A, 404B send information 412,414, respectively, to the base station 402 based on the determinedenergy for each of the CIDs. The information may contain information onall the CIDs or some of the CIDs. When the information containsinformation on only some of the CIDs, the information may contain CIDinformation for non-interfering links with an energy below a thresholdor CID information for interfering links with an energy above athreshold. For example, the wireless device 404A may send theinformation 412 containing the list CID1, CID3 in decreasing determinedenergy and the wireless device 404B may send the information 414containing the list CID2, CID3 in decreasing determined energy.

When the CID broadcast includes device identifiers and the informationincludes CID information for interfering links, the wireless devices404A, 404B may also send information on which wireless devices are usingthe reported CIDs. For example, the wireless device 404A may determinethat wireless devices 406A, 406B are utilizing CID1 and that thewireless device 409B is utilizing CID3, and the wireless device 404B maydetermine that the wireless devices 407A, 407B are utilizing CID2 andthat the wireless device 409A is utilizing CID3. In such aconfiguration, the wireless device 404A may send the information 412containing the list CID1, CID3 along with the device identifiers of thewireless devices 406A, 406B, and 409B, and the wireless device 404B maysend the information 414 containing the list CID2, CID3 along with thedevice identifiers of the wireless devices 407A, 407B, and 409A.

After the information 412, 414 is sent, at least one of the wirelessdevices 404A, 404B receives a CID 416, 418, respectively, from the basestation 402. The CID is one of CID1, CID2, CID3, and CID4 determinedbased on the information 412, 414. For example, the base station 402 maycompare the information 412 including the CIDs CID1 and CID3 and theinformation 414 including the CIDs CID2 and CID3 to determine a commonsubset of CIDs CID1, CID2, and CID3. The base station 402 may thendetermine the subset of CIDs excluded from the common set, such as thesubset of CIDs including CID4. From that subset of CIDs, the basestation 402 may select CID4 for the wireless devices 404A, 404B, andsend the CID4 416, 418 to at least one of the wireless devices 404A,404B, respectively. The base station 402 may send the CID4 to only oneof the wireless devices 404A, 404B, relying on the receiving wirelessdevice to communicate the received CID to its peer.

As discussed supra, rather than send CID information for interferinglinks, the wireless devices may send CID information for non-interferinglinks. In such a configuration, the base station 402 would select a CIDfrom the common subset of CIDs determined based on the comparison of thereceived CIDs.

The wireless devices may send additional information to the base station402 to enable the base station 402 to make a more informed decision whenselecting the CID. In one configuration, the wireless devices determinea signal to inference ratio (SIR) associated with each of the CIDs andsend the information to the base station 402. The SIR is the transmitenergy for an assigned CID divided by the determined energy for each ofthe CIDs. With this information, the base station 402 will know theextent of protection links have from non-interfering links. Somenon-interfering links will be closer to the threshold of beinginterfering than other links. The information can be used by the basestation 402 to provide a more efficient reuse of CID resources (e.g., byreusing the CIDs with non-interfering links that are closest to thethreshold of interference), or to provide the best protection fromexisting links (e.g., by choosing the CIDs that provide the highest CIRprotection).

In another configuration, the wireless devices determine a number ofactive links in their vicinity and send the information to the basestation 402. The base station 402 can use this local topologyinformation to determine whether tighter packing of CIDs is required dueto the CID resource being constrained or whether the CID distributionmay be spread out to provide maximum protection for existing links dueto the CID resource being large.

In another configuration, the wireless devices determine a channelstrength between themselves and their peer and send the information tothe base station 402. The channel strength is associated with a linklength, i.e., a distance between two wireless devices in peer-to-peercommunication. The base station 402 may group the links into differentCID groups based on the reported link length. To group the links intodifferent CID groups, the base station 402 associates each of the CIDgroups with a different channel strength range of values and selects aCID for a link from a CID group if the reported channel strength iswithin the channel strength range of values for the CID group. Groupingthe links into different CID groups can be especially useful if thelinks are scheduled based on their CIDs, such as in FlashLinQ wherelinks obtain a medium access priority that is a function of the currenttime and their CID.

Alternatively, the base station 402 may group the links into differentCID groups based on local topology information determined based on thenumber of active links reported by each of the wireless devices. Bygrouping the links into different CID groups based on local topologyinformation, the base station 402 may be able to reduce or to eliminatethe so called “cascade yielding problem.” The cascade yielding problemis described with respect to FIG. 10.

FIG. 10 is a diagram for illustrating the cascade yielding problem. Asshown in FIG. 10, wireless device D1 is communicating with wirelessdevice D2 in a first link, wireless device D3 is communicating withwireless device D4 in a second link, and wireless device D5 iscommunicating with wireless device D6 in a third link. The first linkhas a medium access priority of 1, the second link has a medium accesspriority of 2, and the third link has a medium access priority of 3. Inthe cascade yielding problem, if the second link determines that itwould interfere with the first link, the second link Rx-yields to thefirst link that has a higher medium access priority. In addition, if thethird link determines it would interfere with the second link, the thirdlink Rx-yields to the second link that has a higher medium accesspriority. With both the second and third links yielding, only the firstlink communicates in that particular traffic slot. However, assuming thethird link would not interfere with the first link, both the first linkand the third link could have communicated in the traffic slot withoutinterference. As such, in the cascade yielding problem, Rx-yieldingcascades among successively lower priority links and results in a linkyielding to a link that itself is yielding.

By knowing the local topology of the wireless devices, the base station402 can help to reduce the cascade yielding problem by assigning thefirst, second, and third links to different CID groups based on apreferred medium access priority. For example, assume the CID groupsinclude a high priority CID group, a medium priority CID group, and alow priority CID group. The base station 402 can assign the first linkto the high priority CID group, the third link to the medium priorityCID group, and the second link to the low priority link group. Throughthe CID group assignment, the third link will not Rx-yield to the firstlink and the second link will Rx-yield to the third link, thus thecascade yielding problem can be avoided and both the first link and thethird link may communicate concurrently in the particular traffic slot.

FIG. 11 is a flow chart 500 of a first method of a wireless device, suchas wireless device 404A. As shown in FIG. 11, the wireless device 404Adetermines an energy on each of a plurality of resources forbroadcasting CIDs (502). In addition, the wireless device 404A sendsinformation to a base station 402 based on the determined energy foreach of the CIDs (504). Furthermore, the wireless device 404A receives aCID from the base station 402 (506). The CID is one of the CIDsdetermined based on the information (506).

FIG. 12 is a flow chart 600 of a second method of a wireless device,such as wireless device 404A. As shown in FIG. 12, the wireless device404A may rank a subset of the CIDs based on the determined energy foreach of the CIDs (602). In such a configuration, the information sent tothe base station 402 by the wireless device 404A is further based on theranked subset of CIDs (610). The wireless device 404A may determine anSIR associated with each of the CIDs (604). The SIR is based on atransmit energy for an assigned CID and on the determined energy foreach of the CIDs (604). In such a configuration, the information sent tothe base station 402 by the wireless device 404A is further based on theSIR associated with each of the CIDs (610). The wireless device 404A maydetermine a number of active links in a vicinity of the wireless device404A (606). In such a configuration, the information sent to the basestation 402 by the wireless device 402 is further based on thedetermined number of active links (610). The wireless device 404A maydetermine a channel strength between the wireless device 404A and asecond wireless device 404B with which the wireless device 404A is inpeer-to-peer communication (608). In such a configuration, theinformation sent to the base station 402 by the wireless device 404A isfurther based on the determined channel strength (610). The wirelessdevice 404A sends the gathered information to the base station 402(610). The information is based on a determined energy for each of theCIDs and one or more of ranked CIDs, SIR information, a number of activelinks, and a channel strength (610).

FIG. 13 is a conceptual block diagram 700 illustrating the functionalityof a first exemplary apparatus 100. The apparatus 100 may be a wirelessdevice, such as the wireless device 404A. The apparatus includes amodule 702 that determines an energy on each of a plurality of resourcesfor broadcasting CIDs. In addition, the apparatus 100 includes a module704 that sends information to a base station based on the determinedenergy for each of the CIDs. Furthermore, the apparatus 100 includes amodule 706 that receives a CID from the base station. The CID is one ofthe CIDs determined based on the information. The apparatus 100 mayinclude additional modules that perform each of the steps in theaforementioned flow charts of FIG. 11 and FIG. 12. As such, each step inthe aforementioned flow charts may be performed by a module and theapparatus 100 may include one or more of those modules.

FIG. 14 is a flow chart 800 of a first method of a base station, such asthe base station 402. As shown in FIG. 14, the base station 402 receivesfirst information about a first plurality of CIDs from a first wirelessdevice (802). The base station 402 receives second information about asecond plurality of CIDs from a second wireless device (804). The basestation 402 compares the first information and the second information todetermine a subset of CIDs based on the first plurality of CIDs and thesecond plurality of CIDs (806). The base station 402 selects a CID basedon the subset of CIDs (808). The base station 402 sends the selected CIDto at least one of the first wireless device or the second wirelessdevice (810).

In one configuration, the first information includes the first pluralityof CIDs ranked based on a determined energy on each of a plurality ofresources for broadcasting the first plurality of CIDs, and the secondinformation includes the second plurality of CIDs ranked based on adetermined energy on each of a plurality of resources for broadcastingthe second plurality of CIDs. For example, the base station 402 mayreceive the first information 412 that includes a CID list CID1, CID3that is ranked in order of decreasing energy on each of the resourcesfor broadcasting the CIDs. In addition, the base station 402 may receivethe second information 414 that includes a CID list CID2, CID3 that isranked in order of decreasing energy on each of the resources forbroadcasting the CIDs.

In one configuration, the base station 402 compares the firstinformation 412 and the second information 414 by comparing the rankedfirst plurality of CIDs CID1, CID3 and the ranked second plurality ofCIDs CID2, CID3 to determine a ranked common subset of CIDs CID1, CID2,CID3. In such a configuration, the base station 402 selects the CIDbased on the ranked common subset of CIDs. For example, the base station402 may select CID4, which is not in the list. For another example, ifthere were no other CIDs from which to choose, the base station 402 mayselect CID3, which is ranked last in the list and corresponds to a CIDwith the least determined energy among the available CIDs. As discussedsupra, the received information may include a ranked list ofnon-interfering CIDs. The base station may then compare the ranked CIDsto determine a common subset of non-interfering ranked CIDs and selectthe CID from among the subset.

In one configuration, the first information is based on an SIRassociated with each of the first plurality of CIDs and the secondinformation is based on an SIR associated with each of the secondplurality of CIDs. In such a configuration, the base station 402 mayselect the CID in both the first plurality of CIDs and the secondplurality of CIDs associated with an SIR greater than a threshold. Forexample, the first plurality of CIDs may include the non-interferingCIDs CID4, CID3 and the second plurality of CIDs may include thenon-interfering CIDs CID4, CID3. The base station 402 may select the CIDfrom among the CIDs CID4, CID3 that is associated with an SIR greaterthan a threshold. If the reported SIR associated with the CID4 isgreater than a threshold for both of the wireless devices 404A, 404B andthe reported SIR associated with the CID3 is less than the threshold forone or both of the wireless devices 404A, 404B, the base station 402would select CID4 for the wireless devices 404A, 404B.

In one configuration, the base station 402 selects the CID that wouldavoid causing a CID collision with another wireless device in thevicinity of the wireless device. In another configuration, the firstinformation includes a number of active links in a vicinity of the firstwireless device in addition to reported SIR information and the secondinformation includes a number of active links in a vicinity of thesecond wireless device in addition to reported SIR information. In sucha configuration, the base station 402 selects the CID associated with anSIR greater than a first threshold when the number of active links inthe vicinity of the first wireless device and the number of active linksin the vicinity of the second wireless device is less than a secondthreshold. In addition, the base station 402 selects the CID with an SIRgreater than a third threshold less than the first threshold when thenumber of active links in the vicinity of the first wireless device andthe number of active links in the vicinity of the second wireless deviceis greater than a fourth threshold. For example, if both the firstwireless device and the second wireless device report a number of activelinks less than the second threshold (i.e., a relatively small number ofactive links), the base station 402 will select a CID associated with anSIR greater than a first threshold (i.e., a higher SIR). As such, whenthe CID resource is large, the base station 402 spreads out the CIDdistribution. For another example, if both the first wireless device andthe second wireless device report a number of active links greater thanthe fourth threshold (i.e., a relatively large number of active links),the base station 402 will select a CID associated with an SIR greaterthan the third threshold that is less than the first threshold (i.e., alower SIR closer to the threshold of being interfering). The thirdthreshold is high enough such that other links using the CID would beconsidered non-interfering, but is lower than the first threshold. Assuch, when the CID resource is constrained, the base station 402 packsthe CIDs tighter.

FIG. 15 is a flow chart 900 of a second method of a base station, suchas the base station 402. In one configuration, the base station 402groups the CIDs into a plurality of groups based on channel strength(902). For example, the base station 402 may group the CIDs into aplurality of groups by associating each of the plurality of groups witha different channel strength range of values. The base station 402receives from at least one of the first wireless device or the secondwireless device a channel strength between the first wireless device andthe second wireless device (904). Based on the received information, thebase station 402 selects a CID that is in the group corresponding to thereceived channel strength (906). For example, assuming there are fourCIDs, the base station 402 may group the CIDs CID1 and CID2 into a firstgroup associated with channel strengths above a threshold (i.e., mid tohigh channel strengths, short links) and the CIDs CID3 and CID4 into asecond group associated with channel strengths below the threshold(i.e., mid to low channel strengths, long links). If the base station402 receives a channel strength from the wireless device 404A that isless than the threshold, the base station 402 assigns a CID to thewireless device 404A from the subset including the CIDs CID3 and CID4.If the base station 402 receives a channel strength from the wirelessdevice 404A that is greater than the threshold, the base station 402assigns a CID to the wireless device 404A from the subset including theCIDs CID1 and CID2.

After the wireless devices 404A, 404B utilize the assigned CID, the basestation 402 may reselect their CID based on a channel strength betweenthe wireless device 404A and the wireless device 404B. As shown in FIG.15, the base station 402 receives a second channel strength between thefirst wireless device and the second wireless device and the CIDutilized by the first wireless device and the second wireless device(908). The base station 402 determines whether the CID is in a groupcorresponding to the second channel strength (910). The base stationreselects the CID when the CID is not in the group corresponding to thesecond channel strength (912). For example, if the wireless devices404A, 404B are utilizing CID4 and report a channel strength that isgreater than the threshold, the base station 402 will reselect the CIDto a CID in the group corresponding to the high channel strengths. Assuch, the base station 402, will reselect the CID utilized by thewireless devices 404A, 404B by selecting CID1 or CID2 and informing thewireless devices 404A, 404B of the new selection.

FIG. 16 is a conceptual block diagram 1000 illustrating thefunctionality of a second exemplary apparatus 100. The apparatus 100 maybe a base station, such as the base station 402. The apparatus 100includes a module 1002 that receives first information about a firstplurality of CIDs from a first wireless device. The apparatus 100further includes a module 1004 that receives second information about asecond plurality of CIDs from a second wireless device. The apparatus100 further includes a module 1006 that compares the first informationand the second information to determine a subset of CIDs based on thefirst plurality of CIDs and the second plurality of CIDs. The apparatus100 further includes a module 1008 that selects a CID based on thesubset of CIDs. The apparatus 100 further includes a module 1010 thatsends the selected CID to at least one of the first wireless device orthe second wireless device. The apparatus 100 may include additionalmodules that perform each of the steps in the aforementioned flow chartsof FIG. 14 and FIG. 15. As such, each step in the aforementioned flowcharts may be performed by a module and the apparatus 100 may includeone or more of those modules.

Referring to FIG. 1, in one configuration, the apparatus 100 forwireless communication is a wireless device and includes means fordetermining an energy on each of a plurality of resources forbroadcasting CIDs, means for sending information to a base station basedon the determined energy for each of the CIDs, and means for receiving aCID from the base station, the CID being one of the CIDs determinedbased on the information. The apparatus 100 may further include meansfor ranking a subset of the CIDs based on the determined energy for eachof the CIDs. In such a configuration, the information is further basedon the ranked subset of CIDs. The apparatus 100 may further includemeans for determining an SIR associated with each of the CIDs. In such aconfiguration, the SIR is based on a transmit energy for an assigned CIDand on the determined energy for each of the CIDs and the information isfurther based on the SIR associated with each of the CIDs. The apparatus100 may further include means for determining a number of active linksin a vicinity of the apparatus. In such a configuration, the informationis further based on the determined number of active links. The apparatus100 may further include means for determining a channel strength betweenthe apparatus and a second apparatus with which the apparatus is inpeer-to-peer communication. In such a configuration, the information isfurther based on the determined channel strength. The aforementionedmeans is the processing system 114 configured to perform the functionsrecited by the aforementioned means.

In another configuration, the apparatus 100 for wireless communicationis a base station and includes means for receiving first informationabout a first plurality of CIDs from a first wireless device, means forreceiving second information about a second plurality of CIDs from asecond wireless device, means for comparing the first information andthe second information to determine a subset of CIDs based on the firstplurality of CIDs and the second plurality of CIDs, means for selectinga CID based on the subset of CIDs, and means for sending the selectedCID to at least one of the first wireless device or the second wirelessdevice. In one configuration, the means for selecting includes means forselecting the CID associated with an SIR greater than a first thresholdwhen the number of active links in the vicinity of the first wirelessdevice and the number of active links in the vicinity of the secondwireless device is less than a second threshold, and means for selectingthe CID with an SIR greater than a third threshold less than the firstthreshold when the number of active links in the vicinity of the firstwireless device and the number of active links in the vicinity of thesecond wireless device is greater than a fourth threshold. The apparatus100 may further include means for grouping the CIDs into a plurality ofgroups based on channel strength and means for receiving a channelstrength between the first wireless device and the second wirelessdevice. In such a configuration, the selected CID is in the groupcorresponding to the received channel strength. The apparatus 100 mayfurther include means for receiving a second channel strength betweenthe first wireless device and the second wireless device and the CIDutilized by the first wireless device and the second wireless device,means for determining whether the CID is in a group corresponding to thesecond channel strength, and means for reselecting the CID when the CIDis not in the group corresponding to the second channel strength. Theaforementioned means is the processing system 114 configured to performthe functions recited by the aforementioned means.

It is understood that the specific order or hierarchy of steps in theprocesses disclosed is an illustration of exemplary approaches. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the processes may be rearranged. The accompanyingmethod claims present elements of the various steps in a sample order,and are not meant to be limited to the specific order or hierarchypresented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. §112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or, in the case of a method claim, theelement is recited using the phrase “step for.”

1. A method of operating a wireless device, comprising: determining anenergy on each of a plurality of resources for broadcasting connectionidentifiers; sending information to a base station based on thedetermined energy for each of the connection identifiers; and receivinga connection identifier from the base station, the connection identifierbeing one of the connection identifiers determined based on theinformation.
 2. The method of claim 1, further comprising ranking asubset of the connection identifiers based on the determined energy foreach of the connection identifiers, wherein the information is furtherbased on the ranked subset of connection identifiers.
 3. The method ofclaim 1, further comprising determining a signal to interference ratio(SIR) associated with each of the connection identifiers, wherein theSIR is based on a transmit energy for an assigned connection identifierand on the determined energy for each of the connection identifiers,wherein the information is further based on the SIR associated with eachof the connection identifiers.
 4. The method of claim 1, furthercomprising determining a number of active links in a vicinity of thewireless device, wherein the information is further based on thedetermined number of active links.
 5. The method of claim 1, furthercomprising determining a channel strength between the wireless deviceand a second wireless device with which the wireless device is inpeer-to-peer communication, wherein the information is further based onthe determined channel strength.
 6. A method of wireless communication,comprising: receiving first information about a first plurality ofconnection identifiers from a first wireless device; receiving secondinformation about a second plurality of connection identifiers from asecond wireless device; comparing the first information and the secondinformation to determine a subset of connection identifiers based on thefirst plurality of connection identifiers and the second plurality ofconnection identifiers; selecting a connection identifier based on thesubset of connection identifiers; and sending the selected connectionidentifier to at least one of the first wireless device or the secondwireless device.
 7. The method of claim 6, wherein the first informationcomprises the first plurality of connection identifiers ranked based ona determined energy on each of a plurality of resources for broadcastingthe first plurality of connection identifiers, and the secondinformation comprises the second plurality of connection identifiersranked based on a determined energy on each of a plurality of resourcesfor broadcasting the second plurality of connection identifiers.
 8. Themethod of claim 7, wherein the comparing comprises comparing the rankedfirst plurality of connection identifiers and the ranked secondplurality of connection identifiers to determine a ranked common subsetof connection identifiers, and the selecting comprises selecting theconnection identifier based on the ranked common subset of connectionidentifiers.
 9. The method of claim 6, wherein the first information isbased on a signal to interference ratio (SIR) associated with each ofthe first plurality of connection identifiers, and the secondinformation is based on an SIR associated with each of the secondplurality of connection identifiers.
 10. The method of claim 9, whereinthe selecting comprises selecting the connection identifier in both thefirst plurality of connection identifiers and the second plurality ofconnection identifiers associated with an SIR greater than a threshold.11. The method of claim 9, wherein the first information is furtherbased on a number of active links in a vicinity of the first wirelessdevice, the second information is further based on a number of activelinks in a vicinity of the second wireless device.
 12. The method ofclaim 11, wherein the selecting comprises: selecting the connectionidentifier associated with an SIR greater than a first threshold whenthe number of active links in the vicinity of the first wireless deviceand the number of active links in the vicinity of the second wirelessdevice is less than a second threshold; and selecting the connectionidentifier with an SIR greater than a third threshold less than thefirst threshold when the number of active links in the vicinity of thefirst wireless device and the number of active links in the vicinity ofthe second wireless device is greater than a fourth threshold.
 13. Themethod of claim 6, further comprising: grouping the connectionidentifiers into a plurality of groups based on channel strength; andreceiving a channel strength between the first wireless device and thesecond wireless device, wherein the selected connection identifier is inthe group corresponding to the received channel strength.
 14. The methodof claim 13, wherein each of the plurality of groups is associated witha different channel strength range of values.
 15. The method of claim13, further comprising: receiving a second channel strength between thefirst wireless device and the second wireless device and the connectionidentifier utilized by the first wireless device and the second wirelessdevice; determining whether the connection identifier is in a groupcorresponding to the second channel strength; and reselecting theconnection identifier when the connection identifier is not in the groupcorresponding to the second channel strength.
 16. The method of claim 6,wherein the selecting the connection identifier comprises selecting theconnection identifier that would avoid causing a connection identifiercollision with another wireless device in the vicinity of the wirelessdevice.
 17. An apparatus for wireless communication, comprising: meansfor determining an energy on each of a plurality of resources forbroadcasting connection identifiers; means for sending information to abase station based on the determined energy for each of the connectionidentifiers; and means for receiving a connection identifier from thebase station, the connection identifier being one of the connectionidentifiers determined based on the information.
 18. The apparatus ofclaim 17, further comprising means for ranking a subset of theconnection identifiers based on the determined energy for each of theconnection identifiers, wherein the information is further based on theranked subset of connection identifiers.
 19. The apparatus of claim 17,further comprising means for determining a signal to interference ratio(SIR) associated with each of the connection identifiers, wherein theSIR is based on a transmit energy for an assigned connection identifierand on the determined energy for each of the connection identifiers,wherein the information is further based on the SIR associated with eachof the connection identifiers.
 20. The apparatus of claim 17, furthercomprising means for determining a number of active links in a vicinityof the apparatus, wherein the information is further based on thedetermined number of active links.
 21. The apparatus of claim 17,further comprising means for determining a channel strength between theapparatus and a second apparatus with which the apparatus is inpeer-to-peer communication, wherein the information is further based onthe determined channel strength.
 22. An apparatus for wirelesscommunication, comprising: means for receiving first information about afirst plurality of connection identifiers from a first wireless device;means for receiving second information about a second plurality ofconnection identifiers from a second wireless device; means forcomparing the first information and the second information to determinea subset of connection identifiers based on the first plurality ofconnection identifiers and the second plurality of connectionidentifiers; means for selecting a connection identifier based on thesubset of connection identifiers; and means for sending the selectedconnection identifier to at least one of the first wireless device orthe second wireless device.
 23. The apparatus of claim 22, wherein thefirst information comprises the first plurality of connectionidentifiers ranked based on a determined energy on each of a pluralityof resources for broadcasting the first plurality of connectionidentifiers, and the second information comprises the second pluralityof connection identifiers ranked based on a determined energy on each ofa plurality of resources for broadcasting the second plurality ofconnection identifiers.
 24. The apparatus of claim 23, wherein the meansfor comparing compares the ranked first plurality of connectionidentifiers and the ranked second plurality of connection identifiers todetermine a ranked common subset of connection identifiers, and themeans for selecting selects the connection identifier based on theranked common subset of connection identifiers.
 25. The apparatus ofclaim 22, wherein the first information is based on a signal tointerference ratio (SIR) associated with each of the first plurality ofconnection identifiers, and the second information is based on an SIRassociated with each of the second plurality of connection identifiers.26. The apparatus of claim 25, wherein the means for selecting selectsthe connection identifier in both the first plurality of connectionidentifiers and the second plurality of connection identifiersassociated with an SIR greater than a threshold.
 27. The apparatus ofclaim 25, wherein the first information is further based on a number ofactive links in a vicinity of the first wireless device, the secondinformation is further based on a number of active links in a vicinityof the second wireless device.
 28. The apparatus of claim 27, whereinthe means for selecting comprises: means for selecting the connectionidentifier associated with an SIR greater than a first threshold whenthe number of active links in the vicinity of the first wireless deviceand the number of active links in the vicinity of the second wirelessdevice is less than a second threshold; and means for selecting theconnection identifier with an SIR greater than a third threshold lessthan the first threshold when the number of active links in the vicinityof the first wireless device and the number of active links in thevicinity of the second wireless device is greater than a fourththreshold.
 29. The apparatus of claim 22, further comprising: means forgrouping the connection identifiers into a plurality of groups based onchannel strength; and means for receiving a channel strength between thefirst wireless device and the second wireless device, wherein theselected connection identifier is in the group corresponding to thereceived channel strength.
 30. The apparatus of claim 29, wherein eachof the plurality of groups is associated with a different channelstrength range of values.
 31. The apparatus of claim 29, furthercomprising: means for receiving a second channel strength between thefirst wireless device and the second wireless device and the connectionidentifier utilized by the first wireless device and the second wirelessdevice; means for determining whether the connection identifier is in agroup corresponding to the second channel strength; and means forreselecting the connection identifier when the connection identifier isnot in the group corresponding to the second channel strength.
 32. Theapparatus of claim 22, wherein the means for selecting the connectionidentifier selects the connection identifier that would avoid causing aconnection identifier collision with another wireless device in thevicinity of the wireless device.
 33. A computer program product in awireless device, comprising: a computer-readable medium comprising codefor: determining an energy on each of a plurality of resources forbroadcasting connection identifiers; sending information to a basestation based on the determined energy for each of the connectionidentifiers; and receiving a connection identifier from the basestation, the connection identifier being one of the connectionidentifiers determined based on the information.
 34. A computer programproduct, comprising: a computer-readable medium comprising code for:receiving first information about a first plurality of connectionidentifiers from a first wireless device; receiving second informationabout a second plurality of connection identifiers from a secondwireless device; comparing the first information and the secondinformation to determine a subset of connection identifiers based on thefirst plurality of connection identifiers and the second plurality ofconnection identifiers; selecting a connection identifier based on thesubset of connection identifiers; and sending the selected connectionidentifier to at least one of the first wireless device or the secondwireless device.
 35. An apparatus for wireless communication,comprising: a processing system configured to: determine an energy oneach of a plurality of resources for broadcasting connectionidentifiers; send information to a base station based on the determinedenergy for each of the connection identifiers; and receive a connectionidentifier from the base station, the connection identifier being one ofthe connection identifiers determined based on the information.
 36. Anapparatus for wireless communication, comprising: a processing systemconfigured to: receive first information about a first plurality ofconnection identifiers from a first wireless device; receive secondinformation about a second plurality of connection identifiers from asecond wireless device; compare the first information and the secondinformation to determine a subset of connection identifiers based on thefirst plurality of connection identifiers and the second plurality ofconnection identifiers; select a connection identifier based on thesubset of connection identifiers; and send the selected connectionidentifier to at least one of the first wireless device or the secondwireless device.